In the 1941 Beadle–Tatum Neurospora experiment, what relationship did the results support?

The 1941 Beadle–Tatum Neurospora experiment supported the one gene–one enzyme relationship.

George Beadle and Edward Tatum exposed bread mold, Neurospora crassa, to X-rays and isolated mutants that could no longer grow on a minimal nutrient medium. By supplying particular nutrients, they identified biochemical steps blocked by the mutations.

Their results suggested that individual genes controlled individual enzymatic reactions in a metabolic pathway. This became known as the one gene–one enzyme hypothesis and helped connect Mendelian genetics with biochemistry.

The statement was later refined because some genes encode RNA, some proteins contain multiple subunits, and one gene can produce multiple products. Even so, the Neurospora work was a major foundation for molecular genetics and earned Beadle and Tatum the 1958 Nobel Prize in Physiology or Medicine with Joshua Lederberg.